In the prosthetic treatment of lower extremities, it is necessary to provide a set-up adapted to the patient. A set-up is intended to mean the assignment and alignment of all prosthetic components with respect to one another. In the case of patients having a prosthetic knee joint, it is necessary to adjust the orientation and positioning of the prosthetic knee joint and of its rotation axis precisely, and to select and mount the length of the lower limb tube as well as the suitable prosthetic foot. Depending on the patient, it is possible to select a dynamic or secure set-up. In the standing phase, the further the resultant force vector lies in front of the knee axis, the more secure the set-up is, and the closer the resultant force vector is shifted toward the rotation axis of the knee joint prosthesis, the more dynamic the set-up is. If the set-up is secure, the risk of unintended flexion of the prosthetic knee joint is reduced, although relatively high expenditure of energy is necessary when walking. A dynamic set-up makes it easier to flex the prosthetic knee joint in the standing phase both during the heel strike and at the end of the standing phase, as well as in the swing phase. For walking, the user requires comparatively less exertion of force, but the prosthetic knee joint is susceptible to flexion more easily, which may be undesired in some situations.
Besides the set-up of the prosthetic knee joint, the prosthetic foot plays a role which should not be underestimated, since the contact with the ground is established via the prosthetic foot. The prosthetic foot may have a very wide variety of configurations, there being manifold possibilities from a simple wooden block with a plastic shell to a hydraulically controlled, driven prosthetic foot. Conventional prosthetic feet may be worn in shoes, and therefore have an outer appearance approximating that of a normal foot shape. Sports feet are generally not worn in shoes. One problem for users of prostheses of lower extremities is that, when changing shoes, it is necessary to adapt the prosthetic foot to a different heel height compared with standard setting or the original setting. An orthopedic technician has to date adjusted the optimal set-up of a prosthesis for a standard heel height value, but if another heel height is selected for another shoe or a different shoe model, for example with a different heel drop or a different heel height is used it may be necessary to modify the inclination of the prosthetic foot relative to the lower limb tube, in order to carry out heel height adaptation. Otherwise, the entire set-up of the prosthesis is modified. A heel height adjustment may also be necessary when geometrically identical shoes are used. Because of different sole stiffnesses, it may be necessary for a different heel height to be adjusted. A softer heel may require a different heel height than a harder heel.
From the prior art, prosthetic feet are known which have a hydraulic adjustment device, so that an orthopedic technician can carry out an adaptation of the prosthetic foot to modified heel heights. A disadvantage with these solutions is that the orthopedic technician in principle needs to be consulted for each shoe change, with the aim of ensuring a statically and dynamically correct set-up. Furthermore, reproducibility of the adjustment results is not guaranteed.
A prosthetic foot is available under the name “Runway” from the company Freedom Innovations. The adjustment is carried out optionally by means of push-button adjustment or with a hex key.
The company Streifeneder sells a prosthetic foot insert with integrated heel height adjustment under the name “Accent”, with which height adjustment of up to 51 mm can be achieved.